3rd Brigade
- 3 Commando Brigade (United Kingdom)
- 3rd (Ambala) Cavalry Brigade
- 3rd (Meerut) Cavalry Brigade
- 3rd Army Tank Brigade (Australia)
- 3rd Assault Brigade
- 3rd Brigade (Australia)
- 3rd Brigade Combat Team, 10th Mountain Division
- 3rd Brigade Combat Team, 1st Cavalry Division
- 3rd Brigade Combat Team, 1st Infantry Division (United States)
- 3rd Brigade, 104th Division (United States)
- 3rd Brigade, 7th Infantry Division (United States)
- 3rd Brigade, Polish Legions
- 3rd Canadian Infantry Brigade
- 3rd Cavalry Brigade (United Kingdom)
- 3rd Guards Brigade "Kune" (Croatia)
- 3rd Guards Brigade (United Kingdom)
- 3rd Indian Infantry Brigade
- 3rd Indian Motor Brigade
- 3rd Infantry Brigade (South Africa)
- 3rd Infantry Brigade (United Kingdom)
- 3rd Light Armoured Brigade (France)
- 3rd Light Horse Brigade
- 3rd Marine Expeditionary Brigade
- 3rd Mixed Brigade
- 3rd Mountain Brigade (Poland)
- 3rd Parachute Brigade (United Kingdom)
- 3rd Polish Infantry Brigade
- 3rd Signal Brigade (United States)
- 3rd Sustainment Brigade (United States)
- 3rd Tank Brigade (Ukraine)
- Alexandroni Brigade
- III Brigade, Royal Horse Artillery
- III Brigade, Royal Horse Artillery (T.F.)